Airhead Tech Pages

Replacing the Boot!

From: dje@mail.bellcore.com (Don Eilenberger)
Subject: Replacing the boot!
Cc: bmw@rider.cactus.org (bmw Mailing List)
Folks, while I was on vacation recently (with F/C as a second vehicle) - I
noticed that I had a tiny leak from the driveshaft boot.

When I got home, I called Bob's BMW, and the next day had a new boot (about
$6.00) and 4 driveshaft universal joint to tranny bolts (these are 1 time use).

So, tonight, I figured a 15 minute job(1) - and started to work.

First - off come the ground cable for the battery, then the two long hose clamps
holding the old one on. Then since
the old boot had a tiny hole in it - I just took a knife and cut it off - commiting
myself to finish it tonight since tomorrow is supposed to be LOVELY moto weather.

I then took a 10mm 12 point box wrench to the old bolts holding stuff together.
Since I once read noemi's tale of these coming loose - the last time I had
them apart, I used Locktite Blue (the low-hold stuff) on reassembly.

Well - the blue REALLY holds. It took a sharp tug with all my effort and a
good 10mm wrench to break each one free. Holding
the rear brake on prevented the shaft from rotating.

Finally they're all free, and I now can see (after LOTS of futzing around)
that it is NOT POSSIBLE to replace the boot without moving the swingarm back.
So out comes the modified swingarm locknut socket, these get loosened, the
allen driver takes
out the pins, and I'm able to move the arm back enough to get the new boot
sorta in place.

So - reassembly was almost the opposite of disassembly (once I found the spacer
that dropped out) - and I started trying to
get the new bolts (Locktite'd again) in place. These are painful to do - but
not impossible. Curse and keep trying.

Lastly - after all 4 bolts are as tight as I want to make them (just before
things start turning easy is when they're tight!) I start fighting with the
new boot to try to get the two ends where they belong (on tranny and swingarm).
This is a royal PITA! As far as I can see there is NO good way to do this.
Whoever had this as a job at the factory has my sincere sympathy. I've done
this job three or four times, and with the old boot (which I assume had stretched
a bit to fit) it took about 45-90 minutes.

With a brandy new, really flexible, really resiliant boot - it took me a full
two ^#&!( hours to get the damn ends where they belong - somebody tell me THERE
IS A SECRET!! PLEASE!! PLEASE!!).

Anyway - job done, test ride done, no leaks, no vibrations, seems fine. Will
get to ride it to work tomorrow.

Don

PS: (1) = Eilenberger's law of relative time:

Any 15 minute job will take 2-3 hours
Any 1/2 hour job will take ALL DAY
Any all day job may take the rest of your life.